ArcelorMittal has committed €300 million to preparatory work and equipment for its planned electric arc furnace at Dunkirk, France, while progressing the installation of additional electrical steel manufacturing equipment at nearby Mardyck. The developments concern two established investment programmes with different industrial purposes and delivery schedules, rather than newly announced projects or completed manufacturing capacity.
The Dunkirk work forms part of a €1.3 billion investment in lower-emission steelmaking, centred on an electric arc furnace designed to produce approximately two million tonnes of steel annually. Mardyck is the location of a separate electrical steel expansion, valued at approximately €500 million, where the first production lines began operating in March 2026 and further equipment is being prepared for testing in spring 2027.
ArcelorMittal’s October update confirms that €300 million has already been committed to preparing the Dunkirk installation and securing equipment with long manufacturing and delivery times. Site preparation has begun, while the company has submitted the relevant authorisation applications. The expenditure commitment is not evidence that the electric arc furnace has been installed, commissioned, or started producing steel.
A public consultation associated with the Dunkirk development began on 15 October, forming part of the process for considering the proposed installation. Consultation and submission of applications are distinct from final regulatory approval, which remains necessary before the project can proceed through all its planned stages.
The proposed furnace would alter part of the steel production route at Dunkirk. Conventional integrated steelmaking uses a blast furnace to convert iron-bearing raw materials into hot metal, followed by refining in a basic oxygen furnace. The planned electric arc furnace would instead melt a charge containing recycled steel alongside other metallic feedstocks selected to meet the required chemical composition.
Electric arc furnaces use electrodes to generate intense electrical arcs that provide the energy required to melt the charged materials. The process can use substantial quantities of scrap steel, although the proportion depends on the steel grades being produced and the quality and availability of suitable metallic feedstock.
ArcelorMittal’s proposed feedstock mixture includes recycled steel, hot briquetted iron or direct reduced iron, and pig iron. These materials provide different proportions of iron and residual elements, allowing the charge to be adjusted according to the requirements of the finished steel. Scrap alone is not necessarily suitable for every grade, particularly where strict limits apply to residual elements that are difficult to remove during melting.
The project also includes ladle metallurgy equipment, allowing molten steel to undergo further treatment after initial melting. Temperature and composition can be adjusted during this stage, while appropriate processing can help achieve the cleanliness and consistency required before casting. The furnace and ladle treatment equipment therefore perform separate but connected functions within the proposed production route.
ArcelorMittal forecasts approximately 0.6 tonnes of carbon dioxide emissions per tonne of steel from the new production arrangement, around two-thirds below the blast furnace route used for comparison. These are company projections for the proposed process, not measured results from an operating electric furnace at Dunkirk.
Actual emissions will depend on the electricity supplied to the furnace, the production routes used for metallic feedstocks, and the operating conditions ultimately achieved. Direct reduced iron, for example, can be produced using different reducing agents and energy sources, with different emissions consequences. Using an electric furnace does not, by itself, establish a uniform carbon footprint for every tonne of finished steel.
The electrical infrastructure required for the furnace is also substantial. Steel melting creates large and variable electrical loads, making reliable power supply and appropriate transformer and control equipment essential to stable operation. ArcelorMittal has identified its long-term electricity arrangements with EDF as one element supporting the project’s investment case.
Equipment procurement is particularly important at this stage because major electrical and mechanical systems can require extended manufacturing periods. Placing commitments for long-lead components can protect the construction schedule, but those commitments must still be distinguished from physical delivery, installation, and acceptance testing at the steelworks.
At Mardyck, ArcelorMittal is developing a manufacturing route for specialised electrical steels used in motors, generators, and other equipment that depends on controlled magnetic properties. The first three lines began operating in March 2026, establishing a partial production milestone within the wider investment programme.
Further installation work concerns an annealing and pickling line and a reversing rolling mill. The company expects initial testing of the additional equipment in spring 2027. Completion of installation, initial tests, commissioning, and sustained production remain separate steps, and the operation of the first three lines does not establish that the entire Mardyck project is working at its intended capacity.
Electrical steel production requires tighter control of strip thickness, chemical composition, and microstructure than many conventional steel products. In rotating electrical machines, the material is commonly formed into thin laminations that direct magnetic flux while limiting losses associated with changing magnetic fields.
Strip thickness influences eddy current losses, while alloy composition and processing affect the magnetic behaviour of the finished material. Manufacturers must balance electrical efficiency with mechanical properties, particularly in traction motors operating at high rotational speeds and under demanding thermal conditions.
Cold rolling reduces strip thickness and improves dimensional control, while annealing changes the material’s microstructure and magnetic characteristics. Pickling removes surface oxides where required by the production sequence. Bringing these processes together in an integrated route allows the steelmaker to control more of the characteristics needed for demanding electrical applications.
Mardyck’s development complements ArcelorMittal’s existing electrical steel production at Saint-Chély-d’Apcher. The company’s more recent plans have referred to approximately 155,000 tonnes of annual non-grain-oriented electrical steel capacity at Mardyck, rather than the larger figure contained in its original 2022 announcement. This remains planned capacity and should not be equated with verified current output.
The revised project scope and timetable reflect the development of a complex manufacturing installation. Reusing existing industrial buildings can involve additional work to accommodate new processing machinery, services, and material handling arrangements, while the final production sequence must meet both dimensional and metallurgical requirements.
The two projects address different parts of the steel industry. Dunkirk’s proposed electric furnace would change how crude steel is made, while Mardyck’s equipment is intended to expand the manufacture of products with specialised electromagnetic properties. Progress on one project does not establish completion or operating performance at the other.
ArcelorMittal’s earlier Dunkirk material identified 2029 as a start-up target, while subsequent reporting has referred to production ramp-up extending into 2030. Neither date represents achieved commissioning. The next significant milestones are the progression of regulatory authorisations and construction at Dunkirk, alongside the planned spring 2027 equipment tests at Mardyck.
